Addon toolbar - create button to show back button history?

I have a toolbar and want 开发者_如何学运维to create a button that will display a drop down list of the back button history which the user can select and go back to that page.

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Check the Firefox source to see how it's implemented. Open source and all that.

http://mxr.mozilla.org/mozilla-central/source/browser/base/content/browser.xul#507

http://mxr.mozilla.org/mozilla-central/